start up sculpting a human head
Answer - you can import your head by going to File > Import > Wavefront (.obj). If your model isn't a .obj file, select the other option that matches yours. Sculpting tools are in the sculpt panel, top of the screen under Sculpting.

Advice - do not start with a head. If you're new to Blender, start with something simple. Human head is a really complicated model even good artists can struggle with. :-)